RF semiconductor devices operate at high frequencies and generate electronic noise that can adversely affect other components of the circuit that includes the noise-generating device, other devices on the substrate including the circuit and other devices formed on other components in close vicinity to the noise. This is true for the various components that combine to form a package or other assemblies that include the RF device, and also for system on chip, SoC, technologies. The adverse affect upon other components is especially true for high voltage applications such as HVMOS (high voltage metal oxide semiconductor) devices. The noise source may be a device formed on a substrate and which operates at high, RF, frequencies, at high voltages or both. An inductor is another example of a device which can create electrical noise.
The noisy source such as an RF transmitter or RF receiver generates electric noise in the form of EM emissions that can propagate through air or other media such as the substrate itself. Continuous scaling of CMOS technology has resulted in chips operating at even higher frequencies with analog and digital circuits residing in the same chip at ever-closer distances especially in system-on-chip systems. Substrate noise coupling is an effect that is of concern because it can adversely affect the operation of various other devices. Substrate noise can couple into signals through metal routing, device junctions, or the substrate itself.
It would be desirable to isolate electronic noise and prevent it from coupling into other devices and other signals.